In recent years, hair damage, which is caused by chemical treatment with, for example, a hair dyeing agent and a perming agent or physical treatment such as friction and heat, has became a significant problem. A major concern is how to improve the damaged hair. To improve damaged hair means to repair dried-out hair having poor “finger-combability” by imparting sleekness and smoothness to the hair to achieve excellent finger-combability with no dried-out feel.
Traditionally, a known way to improve the damaged hair is to apply a vegetable oil such as a camellia oil and olive oil to hair to replenish a moderate amount of oil so as to impart smoothness and flexibility to hair. Furthermore, in order to improve feeling in use, these vegetable oils have been tried to be used in combination with a compound such as high molecular weight silicone, dimethicone, and volatile silicone.
For example, Patent Literature 1 discloses a hair cosmetic comprising (A) a hydrocarbon having a dynamic viscosity of 2.0-36.0 mm2s−1 at 40° C., (B) an amino-modified silicone, (C) a compound having a polyoxyethylene group and a polyoxypropylene group, and (D) a vegetable oil selected from olive oil, grape seed oil, jojoba oil and camellia oil. The component (C) is a compound of the general formula: R1O—[(C2H4O)p(C3H6O)q]—R2 (wherein R1 and R2 independently denote a hydrogen atom, an alkyl group, or a glyceryl group, and p and q are independently an integer: p=2 to 70, q=2 to 70). The hair cosmetic alleviates stiffness of the damaged hair which is prone to expand due to its stiffness, thus suppressing the expansion of the hair to improve hair manageability, and also reduces stickiness.
Patent Literature 2 discloses a hair cosmetic comprising (A) 1 to 15% by mass of a vegetable oil, (B) a volatile oil, (C) a high molecular weight dimethylpolysiloxane, and (D) a dimethylpolysiloxane having a hydroxyl group, a polyoxyethylene group and/or a polyoxypropylene group. The hair cosmetic is primarily composed of dimethylpolysiloxane. The hair cosmetic imparts conflicting feels to hair: excellent gloss and a smooth and moist touch as well as a dry feel at the same time.
Patent Literature 3 discloses a hair cosmetic comprising (A) a polymer silicone, (B) a volatile hydrocarbon oil, (C) a cholesterol derivative, (D) a low viscosity silicone oil. The hair cosmetic, which exhibits excellent spreadability, smoothness and flexibility when applied to hair, is not sticky to the hair, and can impart a smooth and flexible feel to hair and proper hair manageability after application.
Patent Literature 4 discloses a hair cosmetic comprising predetermined amounts of (A) a hydroxy ether amine compound, (B) a higher alcohol and/or a higher fatty acid, (C) an inorganic acid and/or organic acid, (D) a dimethyl polysiloxane and/or silicone derivative, and (E) an aromatic alcohol, the hair cosmetic having a pH of 2.0 to 7.0. The hair cosmetic exhibits hair-conditioning effect satisfying desirable properties such as smoothness, finger-combability, dry feeling and moistness on both of damaged hair and non-damaged hair from the start of the use to the time after use.
Hair cosmetics composed of only plant oils cause uncomfortable sticky feeling when applied on hair, giving a heavy finish, and thus is unsatisfactory. Accordingly, it has been attempted to use silicone oil as described in Patent Literatures 1 to 4. Thus, the use of silicone oil can impart a refreshing feel, resulting in a lighter finish, but it is not sufficient for improving the feeling in user. Furthermore, these hair cosmetics do not contain an ester composed of dipentaerythritol and at least one fatty acid selected from the group consisting of fatty acids having 5 to 16 carbon atoms. Furthermore, no description is found that suggests the use of the ester compound.
Patent Literature 5 discloses a liquid ester composition obtained by esterifying a branched isostearic acid represented by the chemical formula: R—C(COOH)H—(CH2CH2)—R (wherein R denotes a branched hydrocarbon having seven carbon atoms) with dipentaerythritol, the liquid ester composition having a viscosity of 100,000 to 2,000,000 mPa·s at 25° C.; a hydroxyl value of 10 to 160; and a cloud point of less than 5° C. The liquid ester composition is prepared through a reaction of dipentaerythritol with a specifically branched stearic acid having 18 carbons. An excellent long-lasting cosmetic film of the liquid ester composition provide not only gloss and a moisture feel comparable to a film of a composition containing polybutene, which has been usually incorporated in cosmetic compositions, but also pigment dispersibility and hydrating ability that the polybutene composition cannot provide.
Patent Literature 6 discloses an oil-based cosmetic comprising (A) a liquid ester composition obtained by esterifying a branched isostearic acid represented by the general formula: R1—C(COOH)H—CH2CH2—R2 (wherein R1 and R2 denote a branched hydrocarbon having seven carbon atoms and may be the same or different), and (B) a silicone resin. The component (A) is an isostearic acid having eighteen carbon atoms, and includes dipentaerythritol pentaisostearate, dipentaerythritol tetraisostearate, dipentaerythritol triisostearate, glyceryl triisostearate, and diglyceryl triisostearate. The component (B) includes trimethylsiloxy silicic acid, perfluoroalkyl-polyalkylsiloxy silicic acid. The invention described in Patent Literature 6 provides an oil-based cosmetic which is excellent in the feel at the time of application, gloss, retention of a moisture feel, and retention of cosmetic effects. The oil-based cosmetic is preferably used as a cosmetic for lip.